Processing device and method of operating the device for processing a coated or uncoated fibrous web

ABSTRACT

A processing device and a method of applying the same for processing a coated or uncoated fibrous web are provided. The device comprises a belt configured to extend around a guiding element, at least one counter-element being disposed outside said belt to establish a contact area with the belt, such that the belt and the counter-element establish therebetween a web processing zone for passing a web to be processed therethrough. The processing zone length is defined by the disposition/adjustment of the belt&#39;s guiding element and/or by the design of the counter-elements. The contact pressure applied to a web in the processing zone is configured to be within the range of between about 0.01 MPa and about 70 MPa.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a processing device and a method ofoperating the device for processing a coated or uncoated fibrous web,such as e.g. paper, board or tissue, comprising a belt adapted to extendaround at least one guiding element, at least one counter-element beingdisposed outside said belt to provide a contact area with the belt, suchthat the belt and the counter-element establish therebetween a webprocessing zone for passing a web to be processed therethrough. In theconcept of this application, the term ‘web processing’ refers to avariety of measures associated with the treatment of a fibrous webproduced in a paper/board machine, such as pressing, drying,calendering, coating, sizing. The processing device may also be afinishing device for a fibrous web, such as e.g. a separate coatingdevice or printing device.

2. Description of Related Art

Various belt calender solutions have been disclosed previously e.g. inFinnish patent 95061, as well as in Finnish patent applications FI971343 and FI 20001025. However, these belt calenders are only suitablefor calendering certain grades of paper or board.

Paper and board are available in a wide variety of types and can bedivided according to basis weight in two grades: papers with a singleply and a basis weight of 25-300 g/m² and boards manufactured inmulti-ply technology and having a basis weight of 150-600 g/m². Itshould be noted that the borderline between paper and board is flexiblesince board grades with lightest basis weights are lighter than theheaviest paper grades. Generally speaking, paper is used for printingand board for packaging.

The subsequent descriptions are examples of values presently applied forfibrous webs, and there may be considerable fluctuations from thedisclosed values. The descriptions are mainly based on the sourcepublication Papermaking Science and Technology, section Papermaking Part3, edited by Jokio, M., published by Fapet Oy, Jyväiskylä 1999, 361pages.

Mechanical-pulp based, i.e. wood-containing printing papers includenewsprint, uncoated magazine and coated magazine paper.

Newsprint is composed either completely of mechanical pulp or maycontain some bleached softwood pulp (0-15%) and/or recycled fiber toreplace some of the mechanical pulp. General values for newsprint canprobably be regarded as follows: basis weight 40-48.8 g/m², ash content(SCAN-P 5:63) 0-20%, PPS s10 roughness (SCAN-P 76-95) 3.0-4.5 μm,Bendtsen roughness (SCAN-P 21:67) 100-200 ml/min, density 600-750 kg/m³,brightness (ISO 2470:1999) 57-63%, and opacity (ISO 2470:1998) 90-96%.

Uncoated magazine paper (SC=supercalendered) usually contains mechanicalpulp to 50-70%, bleached softwood pulp to 10-25%, and fillers to 15-30%.Typical values for calendered SC paper (containing e.g. SC-C, SC-B, andSC-A/A+) include basis weight 40-60 g/m², ash content (SCAN-P 5:63)0-35%, Hunter gloss (ISO/DIS 8254/1) <20-50%, PPS s10 roughness (SCAN-P76:95) 1.0-2.5 μm, density 700-1250 kg/m³, brightness (ISO 2470:1999)62-70%, and opacity (ISO 2470:1998) 90-95%.

Coated magazine paper (LWC=light weight coated) contains mechanical pulpto 40-60%, bleached softwood pulp to 25-40%, and fillers and coaters to20-35%. General values for LWC paper can be regarded as follows: basisweight 40-70 g/m², Hunter gloss 50-65%, PPS s10 roughness 0.8-1.5 μm(offset) and 0.6-1.0 μm (roto), density 1100-1250 kg/m³, brightness70-75%, and opacity 89-94%.

General values for MFC paper (machine finished coated) can be regardedas follows: basis weight 50-70 g/m², Hunter gloss 25-70%, PPS s10roughness 2.2-2.8 μm, density 900-950 kg/m³, brightness 70-75%, andopacity 91-95%.

General values for FCO paper (film coated offset) can be regarded asfollows: basis weight 40-70 g/m², Hunter gloss 45-55%, PPS s10 roughness1.5-2.0 μm, density 1000-1050 kg/m³, brightness 70-75%, and opacity91-95%.

General values for MWC paper (medium weight coated) can be regarded asfollows: basis weight 70-90 g/m², Hunter gloss 65-75%, PPS s10 roughness0.6-1.0 μm, density 1150-1250 kg/m³, brightness 70-75%, and opacity89-94%.

HWC (heavy weight coated) has a basis weight of 100-135 g/m² and can becoated even more than twice.

Chemical-pulp produced, woodfree printing papers or fine papers includeuncoated—and coated—chemical-pulp based printing papers, in which theportion of mechanical pulp is less than 10%.

Uncoated chemical-pulp based printing papers (WFU) contain bleachedbirchwood pulp to 55-80%, bleached softwood pulp to 0-30%, and fillersto 10-30%. The values with WFU are highly unstable: basis weight 50-90g/m² (up to 240 g/m²), Bendtsen-roughness 250-400 ml/min, brightness86-92%, and opacity 83-98%.

In coated chemical-pulp based printing papers (WFC), the amounts ofcoating vary widely in accordance with requirements and intendedapplication. The following are typical values for once- andtwice-coated, chemical-pulp based printing paper: once-coated basisweight 90 g/m², Hunter gloss 65-80%, PPS s10 roughness 0.75-2.2 μm,brightness 80-88%, and opacity 91-94%, and twice-coated basis weight 130g/m², Hunter gloss 70-80%, PPS s10 roughness 0.65-0.95 μm, brightness83-90%, and opacity 95-97%.

Release papers have a basis weight within the range of 25-150 g/m².

Other papers include e.g. sackkraft papers, tissues, and wallpaperbases.

Board making uses chemical pulp, mechanical pulp and/or recycled pulp.Boards can be divided e.g. in the following main groups according toapplications thereof.

Corrugated board, comprising a liner and a fluting.

Boxboards, used for making boxes and cases. Boxboards include e.g.liquid packaging boards (FBB=folding boxboard, LPB=liquid packagingboard, WLC=white-lined chipboard, SBS=solid bleached sulphite, SUS=solidunbleached sulphite).

Graphic boards, used for making e.g. cards, files, folders, cases,covers, etc.

One board grade comprises wallpaper bases.

SUMMARY OF THE INVENTION

As can be appreciated from the above, there is a wide range of paper andboard grades, and a multitude of various machines are used for makingthe same. Hence, it is an object of the present invention to provide aprocessing device and a method of operating the same, allowing the useof a highly extensive pressure range and application or action time(heat transfer time and/or processing time) in a processing zone, thesame device being applicable for processing a wide variety of coated anduncoated printing papers, boards and other papers, and being applicablee.g. as a preliminary calender upstream of coating, a finishing calenderdownstream of a paper machine or coating, a breaker stack, a wet stackcalender, or as a dryer, a coater, a sizer, a printer and/or a press.The inventive device is conceivable as a replacement e.g. for a softcalender, a multi-nip calender, a machine calender, a shoe calender, ora Yankee cylinder.

In order to fulfill the objects of the invention, a device of theinvention is characterized in that the processing zone length is definedby means of the disposition of the belt's guiding element and/or bymeans of the design of the counter-elements, and that the contactpressure applied to a web in the processing zone is adapted to beadjustable within the range of about 0.01 MPa to about 200 MPa.

On the other hand, a method of the invention for processing a coated oruncoated fibrous web with a processing device is characterized in thatthe method comprises defining the processing zone length by means of thedisposition of the belt's guiding element and/or by means of the designof the counter-element, and that the method comprises adjusting acontact pressure existing in the processing zone to lie within the rangeof about 0.01 MPa to about 200 MPa.

Contact pressure refers to the sum of pressure effects applied to a webwithin a processing zone between a belt and a counter-element, which arecaused by a tension of the belt and/or by a compression force applied bypossible intra-belt press elements. The pressure adjustment of a contactpressure to a certain pressure value or pressure range is effected bychoosing a suitable belt material, which allows the use of a desiredtightness or tension, and, if necessary, suitable press elements capableof increasing pressure in a localized manner over what is achieved bythe belt alone. It should be noted that, depending on an assembly madeup by belt and counter-elements as well as possible press elements, itis possible to cover either a part of the contact pressure adjustmentrange, the transition to another pressure value or pressure range beingeffected by replacing, if necessary, some of the elements included inthe assembly, or to cover, with a suitable assembly, the entire contactpressure adjustment range, which can be e.g. from about 0.01 MPa toabout 70 MPa or even from about 0.01 MPa to about 200 MPa. For example,the compression achieved by belt tension alone is remarkably low whencompared to the compression accomplished with press elements, whereby,in the solutions implemented without press elements, the adjustmentrange lies closer to a lower limit, e.g. within the range of about 0.01MPa to about 5 MPa. When using press elements, the adjustment range canbe e.g. from about 5 MPa to about 70 MPa, preferably from about 7 MPa toabout 50 MPa or e.g. from about 70 MPa to about 200 MPa.

The inventive device comprises preferably a calender, a coater, a sizer,a printer, a dryer, a press, and/or a web cooler. According to theinvention, a number of the above devices can be set successively in acommon fibrous web production line, the sequence being for example apress device, a drying device, a calender, web cooling.

In addition, the inventive device preferably comprises doctor or otherelements provided downstream of the processing zone for cleaning thebelt of a metal belt calender over its side facing the paper web. Thisway, the belt surface can be cleared of lumps of pitch and dirtdeposited thereon from the paper web in a nip. Moreover, the inventivedevice preferably comprises elements for cooling the heated belt of ametal belt calender along its edges. Cooling can be effected in a per seknown manner, for example by means of water or air injection. Cooling isparticularly preferred in the case of running a paper or board web whichis narrower than the belt. By cooling the edges, it is possible toeliminate a high temperature difference otherwise present along the edgeof a web and to relieve the metal belt of stress conditions resultingtherefrom and eventually causing fatigue failures.

One object of the invention is to provide a method for quickly switchinga grade of coated or uncoated paper, board or tissue to be produced in apaper/board machine from one grade to another. The method is implementedby means of a processing device, comprising a belt adapted to extendaround guiding elements, at least one counter-element being disposedoutside said belt to provide a contact area with the belt, such that thebelt and the counter-element establish therebetween a processing zonefor passing a web to be processed therethrough. The method ischaracterized in that the method comprises providing the belt withheating means and/or cooling means for quickly changing the belttemperature, and that the adjustment of a temperature applied to the webis essentially performed by only adjusting the belt temperature.

An object of the invention is a profiling nip established in anembodiment implemented as a processing device provided with a metalbelt, and an arrangement for the grade-specific adjustment of a niplength.

A device according to this additional aspect of the invention ischaracterized in that outside the processing zone is arranged adeflection-compensated nip roll establishing a profiling nip with aroll, the web being adapted to travel through said profiling nip, thatthe processing zone length is defined by means of the disposition of thebelt's guiding element and/or by means of the dimensioning of the roll,and that a contact pressure applied to the web in the processing zone isadapted to be adjustable within the range of about 0.01 MPa to about 200MPa.

The essential concept in this aspect of the invention is that, inaddition to a processing zone (i.e. a long nip), there is provided atleast one profiling nip. The assembly is roughly consistent with a softcalender. The inventive solution is readily capable of providing e.g.desired surface qualities. Furthermore, the solution is structurallysimple. It makes it possible that, if desirable, the componentsessential in terms of proper operation of the device be positionedentirely outside a belt loop.

The present invention relates to a device for drying a fibrous web, saiddevice comprising a dense, air impermeable metal belt, which forms asurface P1 and is adapted to extend around at least one guiding element,at least one counter-element, which forms a surface P2, being disposedoutside said belt to provide a contact area with the belt, the surfacesP1 and P2 establishing therebetween a fibrous web drying zone forpassing the to-be-dried fibrous web through said drying zone, whereinone of the surfaces P1 and P2 is heated and the other is cooled, atleast one porous wire being further adapted to travel between thesurface P1 and the surface P2, such that the fibrous web is in contactwith the heated surface and the wire is in contact with the cooledsurface, the steam which escapes from the fibrous web migrating throughthe wire to the cooled surface and condensing thereon.

The CondeBelt-method, based on condensation drying, for drying paper andboard is known e.g. from publications FI 97485 B1 and FI 99272 B1. Inthe solutions of these publications, a fibrous web to be dried by meansof condensation drying is passed or guided, together with a porous wire,in between two dense, highly heat conductive surfaces, for example metalbelts. The belt, which is in contact with the fibrous web, is heatedand, thus, there is a transfer of heat to the web to vaporize watertherein. At the same time, the other belt, lying against the wire, iscooled, the vaporized water, which has migrated through the wire,condensing on the surface of the metal belt.

In this context, it is particularly notable that the CondeBelt-processrequires a sufficiently long dwell time in order to function properly.For example, the 1-5 ms dwell time of conventional nips is too short.Thus, practicing a solution like the CondeBelt-method creates a need toemploy a sufficiently long contact area for the effective drying of afibrous web.

The prior art embodiments of the CondeBelt-process make use of thecondensation of pressurized steam to provide heating for the hot sidewire and, on the other, pressurized cooling water for cooling the coldside, as described in the cited publication FI 97485 B1. On the otherhand, in the solution of the cited publication FI 99272 B1, the hot sideheating is effected by means of pressurized hot water. One crucialfunction of the pressurization is to sustain the equilibrium of forcesexisting on opposite sides. As a downside, however, this type ofsolution requires awkward, expensive and high-maintenance insulationsand pressurized chambers. Regarding its overall structure, theCondeBelt-type of implementation has also the drawback that the lengthof a drying zone cannot be manipulated any longer, nor can it bereadjusted after installation.

On the other hand, the preamble of this application discloses aprocessing device, applicable to processing a paper and board web andprovided with a metal belt, and a technical principle for theimplementation thereof. It comprises using a belt and a counter-elementdisposed outside the belt to establish a compression contactsubstantially longer than in presently available calenders, the lengthand compression pressure thereof being variable and adjustable in aversatile manner.

A target of the invention is to provide a solution which combines thebenefits gained by a metal-belt provided processing device of theinvention and those offered by the CondeBelt-process. This enables, onthe one hand, making use of the beneficial aspects of theCondeBelt-process for the effective and high-speed drying of a fibrousweb as well as, on the other hand, the advantages of a metal-beltprovided processing device in terms of a wide-range adjustability forthe length of a fibrous web processing zone and the fibrous webprocessing time, and also for other process parameters.

In order to implement this additional aspect of the invention, a deviceof the invention is characterized in that the belt extends about acounter-element in compliance with its surface, that the drying zonelength is adapted to be adjustable by means of the disposition of thebelt's guiding element/elements and/or by means of the design of thecounter-element/elements, and that a contact pressure applied to thefibrous web is adapted to be adjustable within the range of about 0.01MPa to about 70 MPa, such that the contact pressure applied to thefibrous web in the drying zone is higher than a steam pressure generatedin the vaporization process of water contained in the fibrous web.

The inventive solution provides a device for drying a fibrous web, whichenables the use of a very extensive application or action time (heattransfer time and processing time) and temperature range, as well aspressure range, in a drying zone.

One object of the invention is a processing device for compressing acoated or uncoated fibrous web, such as a web of paper and board, woodfiber board, for packing and/or dewatering the web. The processingdevice comprises a belt adapted to extend around at least one guidingelement, at least one counter-element being disposed outside said beltto provide a contact area with the belt, such that the belt and thecounter-element establish therebetween a web processing zone for passinga web to be processed therethrough.

The function of a paper machine's press section is to remove water froma wet fibrous web (dry content 15-20%) as effectively as possible, suchthat, upon passing over to a dryer section, the dry content would be ashigh as possible (in practice about 50-55%). In contemporary wetpresses, a web is conveyed to a nip contact, wherein the web iscompressed against an absorbent felt in such a way that water is drivenunder the force of pressure loads from web to felt. Commonly applied arepress solutions based on a conventional roll nip or a so-called shoenip. The press nip can be provided either with a single felt lining,whereby a felt is present on one side of the web only, or with a doublefelt lining, whereby water escapes into felts present on either side.

In addition to conventional wet pressing, which involves no heating of apaper web to be dried, there are also a variety of prior known hotpressing methods. Hot pressing involves heating a web, yet the webtemperature does not exceed 100° C. If this temperature is exceeded, theprocess is called super-hot pressing or high intensity pressing. Anotherapplied term is impulse pressing. The principle of hot pressing methodsis to enhance a press drying process both by lowering the viscosity ofwater as a result of heating and by bringing the water to vaporizationat some point in the compression process.

The principal dewatering mechanisms can be divided roughly into threemain categories. Firstly, dewatering may occur as a result of thepacking or compaction of the composition. Heating also enhances flowingby reducing the viscosity of water. This type of mechanism is dominatingin conventional wet pressing and hot pressing. Secondly, dewatering maytake place by way of the development or expansion of steam, i.e. wateris displaced by steam, the term applied being so-called impulsepressing. In order to create an impulse effect, the temperature must besufficiently high for water to vaporize at a presently applied pressure.A third mechanism comprises flashing or flash-drying. It involves atransfer of so much heat to paper that temperature exceeds 100° C., yetthe water is not immediately vaporized at a presently applied pressurebut, instead, the vaporization occurs suddenly only as a result of apressure drop as the nip opens. Thus, the water escapes from a fibrousweb simply by vaporization. All these phenomena are involved in hotpressing, but the impact thereof on dewatering depends on case-specificconditions.

Regarding the function of a press, it is an essential feature whetherthe pressing process is “compression limited” or “flow limited”. In theformer case, the compression of a composition sets a limit todewatering, and pressing can only be enhanced basically by increasingthe compression pressure. In the latter case, on the other hand, thelimit is set by a viscous flow resistance, and dewatering can beenhanced by extending a dwell time. In a device of the invention,introduced in the preamble, for processing a coated or uncoated fibrousweb, an essential component is a belt loop or circle, which enablessetting a fibrous web in a substantially longer-than-before pressingcontact with a counter-element. The belt solution also provides aneasier-than-before control over the length and pressure of a contactzone. Furthermore, a fibrous web can be heated effectively by means ofthe belt. Thus, an essential concept according to this aspect of theinvention is to apply the technical benefits offered by a processingdevice set forth in the preamble to a pressing process, and particularlyto a drying process.

A device of the invention is characterized in that the device isprovided between a belt and a counter-element with at least one porousfelt and/or wire for receiving the water removed from a fibrous web,that the processing zone length is defined by means of the dispositionof the belt's guiding element and/or by means of the design of said atleast one counter-element, and that a contact pressure applied to theweb in the processing zone is adapted to be adjustable within the rangeof about 0.01 MPa to about 70 MPa.

Essentially, the idea is to increase the length of a pressing zone andthus to extend the application or action time of a press. This isaccomplished by designing the passage of a belt loop to be modifiable bymeans of guiding or guide rolls, whereby the length of a press zone(“overlap angle”) can be readily adjusted. The belt loop is supportedand guided by means of separate guiding rolls, the location and/orposition of one or more guiding rolls being preferably adjustable.

By virtue of a longer dwell time, the inventive solution is capable ofachieving a higher dewatering rate, especially in flow-limitedcircumstances. In addition, the opening stage, i.e. the emergence of aweb from a pressing zone, can be controlled better than before for thusavoiding delamination, which may occur if the opening takes place tooquickly.

The method is particularly suitable for just, a so-called press section,wherein the dewatering is primarily based on mechanical compression anda supplementary thermal effect (change of viscosity, vaporization), byusing traditionally a conventional press, a shoe press, a hot press, ora an impulse drier.

In terms of press section, the notable essential benefits offered by themethod include first a long and better-than-before adjustable pressingzone. The zone length, the efficiency of heat transfer, and thedistribution of a compression load (pressure profile) are more easilycontrollable. A particular advantage in this respect is achieved in hotpressing and impulse pressing, in which the above-mentioned delaminationconstitutes a problem. In addition, the novel solution and selection ofproper materials provide an adjustment window substantially moreextensive than before for the process and make the process moreeffective. Moreover, the dosage of heat can be effected in a moreversatile manner. For example, the induction heating of a metal belt canbe implemented upstream of or within the zone.

The method is also applicable to dryer section, wherein the mostsignificant benefits gained thereby include a more effective contactwith paper compared to contemporary drying wires/cylinders (contactpressure substantially higher than what is achieved by wires), apossibility of a two-sided supply of heat (more symmetrical dryingresult and mechanical properties), as well as a possibility of finishingand glazing the paper surface by means of a smooth belt.

A conventional pressing process is primarily based on the compression ofa web for reducing a pore volume and squeezing a corresponding amount ofwater out of the composition. Hence, during the course of compression,the web remains substantially impregnated with water, without hardly anygas phase existing or evolving. On the other hand, impulse pressing ordrying, wherein the top surface of a web is subjected by a thermal rollto such a powerful heating that water vaporizes and the expanding steamforces water to flow out of the web, is, at least on the level ofprinciple, based on the displacement action of vaporized water (gas).Liquid phase (water) is being blown by water vapor out of thecomposition to be dried.

On the other hand, in terms of controlling the operation of a press, ahighly essential feature is the selection of a correct pressure leveland distribution, as well as a nip dwell time. In a shoe press, thepressure level is in the order of a few MPa's, the dwell time inhigh-speed machines being in the order of less than 10 ms, and evenotherwise commonly in the order of less than 40 ms. In roll presses, thepressure is higher but the dwell time is less than 2 ms. Generallyspeaking, it can be concluded that, especially in flow-limited pressingconditions (high-caliper grades), it is considerably more preferable toincrease the application time of a pressing pulse than the maximumpressure. Hence, the trend is towards a longer pressing zone.

Accordingly, it is one object of the invention to provide a method, inwhich the drying of a fibrous web effected by means of pressing isenhanced, such that the pressure of a compressed gas present in feltsand a fibrous web participates in the displacement of water contained inthe fibrous web, and which is applicable to wet pressing a fibrous webin paper, board and chemical pulp machines. In order to achieve thisobject, a method of the invention comprises drying a web of paper/boardby pressing it in a processing device, comprising a belt adapted toextend around at least one guiding element, at least one counter-elementbeing disposed outside said belt to provide a contact area with thebelt, such that the belt and the counter-element establish therebetweena web processing zone for passing a web to be processed therethrough,the method being characterized in that the processing device used in themethod is provided on either side of a web (W) with a pore volume, thatat least on one side of the web the pore volume is established in acompressible felt/wire, in which method the fibrous web (W) to be driedis conveyed in contact with said pore volumes through the processingzone, in which the latter are subjected to a pressing action, wherebythe felt/wire compresses and at the same time the pressure of a gaspresent in its pores increases, causing the flow of gas against the weband thus forcing the water contained in the web towards the pore volumepresent on the other side of the web.

The method comprises pressing a fibrous web in a long pressing zoneaccording to the above-described invention between two bearing surfacestogether with one or more porous and compressible felts/wires.Particularly preferred is the use of a pressing zone established by ametal belt and a roll. The roll-encircling belt provides a long contact,the belt tension being capable of providing a contact pressure in theorder of 0-5 MPa. In addition, an extra load can be provided by using aconventional shoe roll for establishing a more localized high-pressurearea. The zone length can be as much as 5 m for a truly long dwell timeof 100-500 ms, even 1000 ms. The solution according to this aspect ofthe invention offers benefits similar to those already mentioned, suchas e.g. a long and better-than-before adjustable pressing zone, thelength, heat transfer efficiency and compression load distribution(pressure profile) of which are more easily controllable and in whichthe adjustment window for the process can be made substantially largerand the process more effective. In addition, the dosage of heat can beeffected in a more versatile manner.

Furthermore, in view of controlling delamination, it is preferred thatthe pressure distribution of a processing zone be controllable in theweb running direction. The inventive device enables a pressure controlin the web running direction in a variety of ways. For example, this canbe implemented by means of the design and disposition of an extraloading element fitted inside the belt loop. On the other hand, thepressure effect can be controlled separately by means of belt loopslying inside or on top of each other, i.e. in practice by independentadjustment of belt tensions. It is also conceivable that the openingpoints of belt loops lying inside of each other be adapted to occursuccessively at suitable intervals.

The invention relates to a method for treating a coated or uncoatedfibrous web with a sizing agent.

The present invention has managed to combine the benefits of apressurized thermal treatment enhancing the sizing process of a fibrousweb, as well as, on the other hand, the high-speed and wide-rangeadjustability of process conditions provided by a processing device asdescribed above, which is preferably executed as a metal belt calender.Thus, the invention is implemented by applying a hot, long pressingzone. The invention serves to provide a method, which enhances thesizing process of a fibrous web, is suitable for both internal andsurface sizing, and further even allows the use of a very extensivepressure range and application time (heat transfer time and/or treatmenttime) in a processing zone, whereby one and the same device can be usedfor the sizing or other chemical treatment of numerous different coatedand uncoated papers and boards.

In order to achieve these objects of the invention, a method of theinvention is characterized in that at least one sizing process of afibrous web to be treated with a sizing agent comprises the use of abelt device, comprising a metal belt adapted to extend around one ormore guiding elements, at least one counter-element being disposedoutside said belt to provide a contact area with the belt, such that thebelt and the counter-element establish therebetween a processing zonefor passing a web to be processed therethrough, wherein the processingzone length is defined by means of the disposition of the belt's guidingelement and/or by means of the design of the counter-elements, andwherein a contact pressure applied to a web is adjusted by a belttension and/or by the design of press elements and/or by means of acompression force applied by the press elements to the belt to liewithin the range of about 0.01 MPa to about 70 MPa.

An essential feature in the inventive solution is that the processsolution is arranged to be such that, by means of said readilyadjustable heating and pressing zone, a web can be provided withconditions capable of bringing about a reaction of paper and addedchemicals at a fairly high resulting temperature and pressure.Naturally, paper can be supplemented either with only one or more thanone sizing chemicals. Useful chemicals may include, for example, resinsapplicable in internal and surface sizing, synthetic sizes (AKD, ASA,etc.), and other chemicals with a beneficial effect.

Accordingly, the leading concept of the invention is to execute afibrous web sizing process by means of a loop belt included in a metalbelt calender, wherein a belt extends around a counter-element incompliance with its surface over a distance equal to a sufficiently longweb processing zone of an arbitrarily adjustable length. The pressingsurfaces established by means of a metal belt and a counter-element makeup a sort of closed pressure chamber, wherein e.g. the size softening,conveyance, fixing reaction, and bonding of sizing agents take placefaster in a web treated with sizing agents. Furthermore, since theheating is effected from the surface of paper, the paper develops majortemperature and concentration variations in the early stages of heating.The beneficial result is the ability of a size (size vapor) to migratein the perpendicular direction of paper, thus equalizing the sizingeffect in the perpendicular or thickness direction. Thus, even one-sidedsurface sizing works across the entire paper thickness.

The contact pressure of a processing zone is controlled by means of ametal belt tension. In this respect, it is essential that the pressureapplied to a fibrous web be adapted in the processing zone preferably insuch a way that, on the one hand, the steam pressure generated as aresult of heating the fibrous web and, on the other hand, the mechanicalpressure pressing the contact areas or surfaces are in equilibrium orthe latter is higher. Likewise, at the trailing edge of a processingzone, the arrangement of temperature and pressure is preferably suchthat no delamination or excessively powerful discharge of gases can takeplace.

Another notable advantage of the inventive arrangement is that, byvirtue of its high-speed and easy adjustability, a metal belt calenderas described above can be used for quickly switching a grade of paper byadjusting the process conditions to be optimally consistent with the webthickness and properties, as well as with the compositions and amountsof sizing agents.

The described arrangement is particularly suitable for the hydrophobicand strong sizing of paper and board, but it is also conceivable toapply the arrangement for the impregnation as well as coating of paper.In the case of dry coating, the melting and bonding of a coatingmaterial may also be relevant.

One essential observation is that the same device, in which paper ispressed with a smooth, heated contact surface, is also capable ofproviding a calendering and drying effect. It is particularlyconceivable that the enhancing treatment of fibrous web sizing processeseffected by means of a metal belt calender and the calendering of afibrous web be executed simultaneously with one and the same device. Ametal belt calender, which establishes a long zone, is especiallysuitable for the purpose.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The invention and a variety of its applications will now be described inmore detail with reference to the accompanying drawings, in which:

FIG. 1 shows one exemplary embodiment for a device of the invention in aschematic side view,

FIG. 1 b shows one variant for the device of FIG. 1 in a schematic sideview,

FIG. 2 shows a second embodiment for a device of the invention in aschematic side view,

FIGS. 3-7 show a few alternative implementations of the invention,

FIG. 8 is a schematic side view, showing one exemplary embodiment for adevice of the invention, provided with a profiling nip,

FIG. 9 is a schematic side view, showing a second exemplary embodimentfor a device of the invention, provided with a profiling nip,

FIG. 10 is a schematic side view, showing one exemplary embodiment for adevice of the invention, applicable for drying a fibrous web,

FIG. 11 is a schematic close-up of an area A indicated in FIG. 10,visualizing a fibrous web drying process within a drying area,

FIG. 12 is a schematic side view, showing a second exemplary embodimentfor a device of the invention, applicable for drying a fibrous web,

FIG. 13 shows still another embodiment for a device of the invention,applicable for drying a fibrous web,

FIG. 14 is a schematic close-up, showing a portion of still oneembodiment for a device of the invention, applicable for pressing afibrous web,

FIG. 15 is a schematic close-up, showing a portion of a secondembodiment for a device of the invention, applicable for pressing afibrous web,

FIG. 16 shows in a schematic close-up a portion of one embodimentconsistent with the device of FIG. 1, applicable for drying a fibrousweb,

FIG. 17 shows in a schematic close-up a portion of a second embodimentconsistent with the device of FIG. 1, applicable for drying a fibrousweb,

FIG. 18 shows in a schematic close-up a portion of the device of FIG.17, visualizing a fibrous web drying process within a pressingzone/drying area,

FIG. 19 shows in a side view a pilot machine implemented in accordancewith the invention,

FIG. 20 shows the pilot machine of FIG. 18 in a plan view,

FIG. 21 shows schematically one implementation for an LWC paperproduction line.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates one device of the invention executed as a beltcalender, comprising a metal-constructed calendering belt 2, whichextends around guiding rolls 3, at least some of said guiding rollsbeing movable for adjusting the belt 2 to a desired tension. Thecalendering belt 2 travels around a roll 5 disposed on the outsidethereof, a calendering zone being established between the belt 2 and theroll 5. A material web W to be calendered travels through thecalendering zone, being subjected to a desired pressure impulses andthermal effect as a function of time. A dash-and-dot line 9 in FIG. 1represents the pattern of pressure curve when the calendering belt 2 isprovided on the inside thereof with a nip roll 4 functioning as a presselement, which compresses the belt against the roll 5 to establish ahigher-pressure nip area within the calendering zone. On the other hand,a dash line 8 represents the pattern of pressure curve when the contactpressure existing in the calendering zone is created by a belt tensionalone, the nip roll 4 being out of a compressing contact with the belt 2(or when there is no nip roll 4 at all fitted inside the belt 2). Theroll 5, like the nip roll 4 as well, may or may not be adeflection-compensated roll and it is selected from a group, including:an elastic surface roll, such as a polymer-covered roll, arubber-covered roll or an elastomer surface roll, a shoe roll, a thermalroll, a filled roll, and a composite roll. Instead of the roll 4, thepress element may also comprise some other profitable or fixed-profilepress element, which, in addition, can be constituted by severalcomponents or elements successive in the cross machine direction. Thepress element 4, implemented in the form of a roll, may also beconstituted by several components successive in the cross machinedirection. The press element 4 may have its surface designed ascontinuous or discontinuous. Furthermore, the press element 4 can bedesigned to be movable for changing the processing zone length and/orbelt tension.

In the embodiment shown in FIG. 1, the nip roll comprises a shoe roll.Reference numeral 6 represents heating elements, such as for example aninduction heater, an infrared radiator, a gas burner. Heating can bebased also on resistive heating. Especially in the case of a metal belt,the inventive solution can be implemented by applying elevatedtemperatures, for example from higher than about 100° C. to higher thanabout 200° C., and even up to about 400° C., depending on intendedapplication. The elevated temperature, together with a long applicationtime and a wide pressure control range, yields a good calendering resultat both high and low speeds, e.g. at speeds of 100 m/min to 4000 m/min.

Reference numeral 6 b in FIG. 1 indicates heating means with a directeffect on a paper/board web, e.g. an infrared radiator or a microwave/RFheater. Heating can be effected also resistively or with some otherprior known technique.

FIG. 1 b illustrates one variant for the device of FIG. 1, wherein anendless belt 2 travels around guiding rollers 3 and press rolls 4. Theguiding rollers 3 are adapted to be movable for adjusting tension of thebelt and the press rolls 4 are adapted to shift in a direction towards aroll 5, whereby the movement of the guiding rollers 3 enables the belt 2to compress or force the press rolls 4 against the roll 5.

FIG. 1 c shows yet another variant for the device of FIG. 1, wherein thepress roll 4 is adapted to be movable.

FIG. 2 illustrates an exemplary embodiment, wherein a calendering zoneis established between tow calendering belts 2 and 2 a, whereby a roll 5a present inside the belt 2 a can be selected the same way as theabove-mentioned roll 5. The belt 2 may also be provided with an insideroll for establishing a nip with the roll 5 a.

The calender belt 2 used in a belt calender executed according to theinvention may not comprise a metal belt as described above, but,instead, e.g. a steel-reinforced rubber belt, polymer belt or a coatedmetal, rubber or polymer belt. The roll 6 may also be provided with ahard or soft surface. The belt 2 and/or the roll 5 can be smooth insurface or embossed, and a contact area or surface constituted by thebelt and/or the roll with a web W may move at a speed different fromthat of the web W. The belt coating may comprise a permanent orremovable coating. The coating can be granular, liquid, solid, made ofelutriated fines, and the coating may be detachable from the beltsurface in a controlled fashion.

FIGS. 3-7 are schematic illustrations of a few alternativeimplementations for a fibrous web processing device, wherein the shapeof a processing zone is designed by using various counter-elements toprovide a contact area or surface with the belt and various presselements to create a desired pattern for a pressure pulse. Thecounter-elements and the press elements may comprise rotating ornon-rotating rolls or various support bars. Said elements may also beprovided with a crowning or an adjustable profiling for controlling alateral tension and pressure effect of the belt.

FIG. 3 illustrates a processing zone established by a belt 2 and a roll5, wherein a pressure pulse is produced by means of the belt tension.FIG. 4 includes, in addition to the belt 2 and the roll 5, a nip roll 4for applying an extra compression force to a presently treated web. FIG.5 illustrates a substantially planar processing zone established betweentwo belts 2 and 2 a, which solution can also be optionally provided withintra-belt rolls 4 and/or 4 a (depicted with dash lines in FIG. 5) forsupporting the belt 2 or 2 a over the section covering planar zone. Therolls 4 and 4 a can establish a nip with each other. FIG. 6 depicts asolution, wherein two belts 2 travel under the guidance of guidingrollers 3 around two bar elements 8 and 9 constituting a substantiallyflat surface. A processing zone is provided between the belts 2. Theintra-belt element 8 and/or 9 can be stressed or biased against theinner surface of the respective belt 2 for producing a desired pressureimpulse in the processing zone. FIG. 7 shows a solution, wherein thebelt 2 extends around a dish-surface bar 10 and wherein the presselement comprises a convex-surface bar 11, around which runs anotherbelt 2. A processing zone is provided between the belts 2.

A processing device of the invention is also conceivable for use in thedryer section of a paper/board machine, the belt comprising a metal beltand the counter-element, which establishes a contact area therewith,comprising a drying cylinder.

A processing device of the invention enables a supported belt passagethrough a processing zone and allows a controlled fluctuation of the webwidth within a range defined by the belt width. Web feeding is possibleover a full web width and at a high web running speed.

The regulation of moisture/temperature in a presently treated web can beperformed by conventional means, for example by steaming the websurface/surfaces prior to passing the web into a processing zone. Theregulation of moistening/temperature can be used for a desired effect onthe lateral profile of a web and the method provides a possibility for awide-range fluctuation of web moisture.

A method of the invention provides also a possibility of cooling a metalbelt or a thermal roll to a temperature of about −70° C. to +50° C.

For example, the manufacture of glossy printing paper in currenttechnology requires an expensive multi-nip calender. A glossy surface isalso producible at slow speeds, as well as by applying low pressures andlow temperatures, by copying against the surface of a Yankee cylinder.However, the Yankee cylinder is limited in terms of speed and width.

The inventive belt calender allows for the use of considerable speeds,and by additionally using an elevated temperature, e.g. about 250° C.,and by considering a long dwell time in a processing zone, the resultingglazing effect will be equal to what is achieved in the slower Yankeecylinder solution.

Another advantage gained by the inventive solution is a comparativelylow power demand, since the transmission of energy, heat, and power to aweb takes place in a single process in an enhanced manner. The heatdelivered to a web or a coating layer is not able to escape from the webto ambient air but continues its temperature raising effect, thusfacilitating significantly the glazing of a web surface.

The inventive device is preferably provided with means 101 downstream ofa processing zone for cleaning the surface of a belt 2 facing a fibrousweb W in a metal belt calender 1. This is to clear the belt surface oflumps of pitch and dirt deposited thereon from the fibrous web in thenip.

The inventive device is also preferably provided with means 102 forcooling the edges of a heated belt 2 in a metal belt calender 1. Coolingcan be effected, for example, by means of water or gas injection.Cooling is particularly beneficial when running a paper or board webwhich is narrower than the belt. By cooling the edges, the metal beltcan be relieved of a major temperature difference otherwise existingalong the web edge, as well as of stress conditions resulting therefromand possibly causing fatigue fractures.

FIG. 8 shows one solution of the invention, wherein a fibrous web W isfirst guided through a profiling nip N1, established by adeflection-compensated nip roll 26 disposed outside the belt loop of ametal belt calender 1 with a roll 5, and then passed over a guidingelement 27 to a nip N2 between the roll 5 and a belt 2.

The arrangement of FIG. 8 is particularly suitable for boards as one andthe same machine is used for producing coated and uncoated grades.Another idea in this embodiment of a processing device is that, inaddition to a tension of the belt 2, it is also possible to adjust anoverlap angle of the belt in a nip, i.e. the length of a nip. Thisenables running higher-thickness grades with a shorter nip as the speedis lower, and lower-thickness grades with a longer nip. Thus,diverse-thickness boards have only the topliner heated and plasticized,and the thermal energy consumption of a thermal roll will be optimizedat the same time.

The roll 5 comprises preferably a thermal roll. Instead of a single roll5 depicted in FIG. 8, the number of thermal rolls can be possibly evenup to three. On the other hand, the deflection-compensated nip toll 26may comprise a chilled-surface or preferably for example acomposite-shelled, rubber-covered, deflection-compensated roll. Thisresults in a good profiling capability, and the nip is capable ofcalendering, without instability of gloss, those grades which are notcoated after calendering.

According to one preferred embodiment of the invention, it is alsopossible to employ a press element disposed inside a belt loop,particularly a roll 4. Such a preferred solution is depicted in FIG. 9,wherein the roll 4 is designed as a shoe roll and establishes at thesame time with a roll 5 an extra nip, which can be located within orupstream or downstream of the confines of a nip N2 established by theroll 5 and a belt 2. The roll 4 can be preferably made movable the sameway as a guiding element 3, such that, if desirable, it can be used fortightening the belt 2.

It should be noted that a web W can be adapted to travel in the devicein either direction. Profiling can also be provided both upstream anddownstream of the nip. It is conceivable, for example, that FIG. 9 beprovided with a dash-line designated, deflection-compensated nip roll 26to establish a profiling nip with the roll 5 as in the exemplaryembodiment for a device shown in FIG. 8.

It should also be pointed out that the rolls 4, 5 and 26, as well as theguiding elements 3, can be mounted on a common frame or separate frames.In particular, it should be noted that various embodiments of theinvention, such as, for example, in FIGS. 8 and 9, can be set in variousangular positions. For example, it is possible to achieve a zero nipload by means of an appropriate relative disposition/appropriate angularpositions of components.

FIG. 10 illustrates one device of the invention for drying a fibrous webby means of condensation drying, said device comprising ametal-constructed belt 2, which forms a surface P1 and extends around aguiding element 3. The belt 2 is further adapted to extends around acounter-element 5, which is disposed outside the same and which forms asurface P2. The belt 2 and the roll 5 establish therebetween a dryingzone for passing a to-be-dried fibrous web W therethrough. In addition,between the belt 2 and the counter-element 5 is adapted to advance atleast one porous, air permeable wire 31, such that, in this embodimentof the invention, the fibrous web W is in contact with the surface P2heated in the drying zone, and the wire 31 is in contact with the cooledsurface P1. The arrangement is shown in more detail in FIG. 11.

The fibrous web W to be dried travels through the drying zone, beingsubjected to a desired pressure impulse and thermal effect as a functionof time. In response to the heated surface P2, the temperature of watercontained in the fibrous web W rises and the water vaporizes. Thevaporized water migrates through the porous wire 31 onto the cooledsurface P1 formed by the belt 2 for further condensation thereon.

In a highly preferred embodiment of the invention shown in FIG. 10, thesurface P2 is heated and P1 is cooled. The counter-element 5 forming thesurface P2 may most conveniently comprise a thermal roll, which is thecase in the embodiment of FIG. 10. Heating and temperature control ofthe roll 5 are readily feasible for the purpose of the invention. Allprior known heating solutions for a conventional thermal roll can beused. It is also conceivable to use a device of the invention in thedryer section of a paper or board machine, whereby the roll 5functioning as a counter-element comprises a conventional dryingcylinder. In this case, heating and temperature control of the roll 5are performed in a prior known manner by means of steam and byregulating its pressure.

In the configuration of FIG. 10, the surface P2 is formed by a dash-linedesignated metal belt 32, adapted to extend around the roll 5. Thus,heating of the surface P2 can, on the one hand, be effected by heatingthe belt 32 alone or, on the other hand, by the application of heatingboth to the belt 32 and to the roll 5. The application of heating to theroll 5 as well provides a better-than-before control over temperature ofthe belt 32 and the consistency thereof throughout the drying zone as itis in contact with the roll 5 for further enhancing the drying processof a fibrous web. A variety of options are available for heating thebelt 32 and those will be described in more detail later in conjunctionof the exemplary embodiment of FIG. 3, which deals with alternativeheating means for the belt 2.

Respectively, the belt 2, functioning as the cooled surface P1, can haveits cooling effected in a plurality ways, for example by heat transferto a cooling liquid, to an evaporating surface, to a cooling roll orbelt. In FIG. 10, the cooling means applied for cooling the belt 2 areindicated with numeral 34. It is conceivable that the belt 2 be cooled,for example, with a cold water jet, a cold air injection or by someother prior known method. It is likewise conceivable that the belt 2 beprovided in a prior known manner with dehumidifiers 35.

Thus, according to the invention, in order to adjust the belt 2 to adesired tension, at least some of the guiding elements 3 are adapted tobe movable. In addition to the tightness of the belt 2, a contactpressure applied to a fibrous web in the drying zone can be furtherincreased and, at the same time, the composition of a fibrous web itselfcan be influenced by fitting inside the belt 2 additionally at least onepress element 4 for compressing the belt 2 against the counter-element5. In one preferred embodiment of the invention, the press elementcomprises at least one roll 4. The roll 4 may also bedeflection-compensated and it can be selected from a group, including anelastic surface roll, such as a polymer-covered roll, a rubber-coveredroll or an elastomer surface roll, a shoe roll, a thermal roll, a metalroll, a filled roll, and a composite roll. The roll 4 can also beshiftable for varying the processing zone length and/or belt tension.

A dash-and-dot line 9 in FIG. 10 represents the pattern of a pressureimpulse in the case when inside the belt 2 is fitted a roll 4functioning as a press element, in this case a nip roll which compressesthe belt 2 against the roll 5 to establish a higher contact pressurewithin the drying zone. A dash line 8, in turn, represents the patternof a pressure impulse in the case when the contact pressure existing inthe drying zone is established solely by means of a tension of the belt2, the nip roll 4 being out of a compressive contact with the belt 2 orwith no nip roll 4 at all fitted inside the belt 2.

The other main operations in the process, with regard to venting a weband wires/felts, removal of condensate from a wire, as well assupporting the passage of a web and wire, can be implemented basicallyas described in the preambles of the cited publications FI 97485 B1 andFI 99272 B1, and, thus, shall not be explained further at this time.

In another preferred embodiment of the invention shown in FIG. 12, thebelt 2, which forms a surface P1, is heated and the counter-element 5,which forms a surface P2, is cooled, respectively.

In this embodiment, a fibrous web W is in contact with a belt 2, whichforms a surface P1, while a porous wire 31 is in contact with a roll 5,which functions as a cold surface P2. The surface of the roll 5 itselfcan also be made porous, whereby it actually replaces the porous wire 31and a separate wire is not necessarily needed. The roll 5 can also beprovided with a hard or soft surface. Furthermore, the belt 2 and/or theroll 5 can be smooth or embossed in its surface and the contact surfaceestablished by the belt and/or the roll with a web W can travel at aspeed different from that of the web W.

Heating of the belt 2 is feasible, for example, by means of induction orsome other prior known means. In a particularly preferred case, the belt2 can have its heating provided by means of guiding elements 3. Theguiding elements 3 can be heated by any prior known heating method,preferably from inside, with water, steam, or, as especially preferred,with oil or internal combustion. The belt 2 can have its heatingprovided also by means of separate heating units, represented byreference numeral 6, such as, for example, an induction heater, aninfrared radiator, or a gas burner.

The surface P2 or counter-element 5 can have its cooling handled, forexample internally, by the application of the heat transfer principlesof a thermal roll, by circulating a cooling heat carrier in anintra-roll manifold 16. It is also conceivable that vaporization of asuitable refrigerant be effected inside the roll 5, i.e. the roll 5functions as a component in a heat pump process, whereby the recoveredheat could be used elsewhere. In association with the roll 5 arepreferably provided dehumidifiers 35.

In this embodiment, it is also possible to arrange inside the belt 2 atleast one roll 4. which functions as a press element and provides a nipwith the counter-element 5. A fibrous web can be thereby subjected to anextra contact pressure within the nip zone, and hence to have anenhanced effect also on the composition and properties of the fibrousweb. The elevated temperature, together with a long application time anda wide-range pressure control capability, offers a possibility ofapplying a beneficial effect on a fibrous web both at high and lowspeeds, e.g. at speeds of 100 m/min to 4000 m/min.

In this embodiment of the invention, The other main operations in theprocess, with regard to venting a web and wires/felts, removal ofcondensate from a wire, as well as supporting the passage of a web andwire, can be implemented also basically as described in the citedpublications FI 97485 B1 and FI 99272 B1, and shall not be explainedfurther at this time.

In order to establish a contact area, formed by the counter-element 5with the belt 2, and a fibrous web drying zone, it is possible to usecounter-elements in a variety of configurations. As in the exemplaryembodiments shown in FIGS. 1 and 3, the counter-elements and presselements can be rotating or non-rotating rolls. These can additionallybe provided with a crowning for controlling a lateral or crosswisetension of the web. It is also conceivable that the counter-elementcomprises something other than a roll, such as, for example, varioussupport bars. Furthermore, by using diverse press elements, it ispossible to have a desired effect on the pattern and magnitude of apressure impulse applied to a fibrous web in the drying zone.

In an embodiment of the invention, implemented by means of fixed barelements and shown in FIG. 13, heating can be applied to the surface P2and cooling to the surface P1, or vice versa. In the embodiment of FIG.13, a belt 32, functioning as the surface P2, is heated and a belt 2,functioning as the surface P1, is cooled. In order to facilitatetemperature control over the belt 32, heating can also be additionallyapplied to a bar element 5 a, or optionally omitted. Likewise, thesurface P1 can have its cooling applied solely to the belt 2, oradditionally also to a bar element 5 b. The heating and cooling methodsmay comprise all of the above solutions.

FIG. 14 illustrates a portion of a device of the invention, whichcomprises a metal belt 2 as described above and intended for pressing,and especially for drying a fibrous web W, and which is provided betweenthe belt 2 and the web W with a porous felt 51, as well as between theweb and a counter-element 5 with a felt 52, respectively.

In the process of being conveyed into a pressing zone, the fibrous web Wis subjected to a compression force and, as the web compresses, thewater contained therein migrates, being driven by pressure loads, fromthe web into the surrounding felts/wires and remains therein after thepressing zone. The leading concept in a solution of the invention is toexploit the above-described processing device for extending the pressingzone and, consequently, to lengthen the application time of a press.Thus, the belt loop is used for setting a fibrous web in a substantiallylonger-lasting compressive contact with a counter-element. At the sametime, the length and pressure of a contact area can be controlled moreeasily than before. Likewise, the opening stage can be controlled betterand, thus, delamination is avoided.

A function of the felts is to receive an ingredient migrating theretofrom a fibrous web, in this case, water. Another function of the feltsis to operate as a flexible element within the pressing zone and tosupport a web elsewhere outside the pressing zone. The pressing zone caneither be provided with a single felt lining, the felt being only usedon one side of a web W, or with a double felt lining, the felt beingused on both sides of the web W. It is also conceivable that more thanone felt be provided on one side of the web. It is further conceivablethat, instead of a felt, the web be provided on one side or on bothsides with an appropriate type of wire.

A belt loop is supported and guided by means of separate guiding rolls 3(e.g. as shown in FIG. 1). The location and position of one or moreguiding rolls 3 can be adjusted. What is essential in this respect isthat the passage of a belt loop is modifiable by means of the guidingrolls 3 in such a way that the length of a pressing zone (“overlapangle”) can be readily controlled. Likewise, the opening stage can becontrolled in such a way that delamination of a web W cannot happen. Thebelt 2 in a belt loop may comprise a metal belt or a composite metalbelt.

In this case, as well, the belt loop is used for setting a fibrous web Win a substantially longer-lasting compressive contact with acounter-element 5. The length and pressure of a contact area are alsomore easily controllable than before. Likewise, the opening stage can becontrolled better to thus avoid delamination. Pressure control in apressing zone can be further improved by regulating individually thepressure effect of a belt 2 as well as possibly added belt loops lyinginside or on top of each other, i.e., in practice, by adjusting atension thereof independently of each other. In addition, the openingpoints of various belt loops can be adapted to occur successively atappropriate intervals, as visualized e.g. in FIG. 14. The belt 2establishes a pressure zone 91 and the felt or the wire 51, the latterbeing especially preferred in this case, establishes a pressure zone 92.

Inside a belt loop there may be one or more support elements 4 for eachcounter-element 5, the purpose of which is to increase a compressionload resulting from the tension of a belt 2. Thus, the pressure in apressing zone between the counter-element 5 and the belt loop resultsfrom a tension of the belts 2 and the felts/wires 51, 52, and frompossible extra loads created by the support elements 4.

It is further possible to use the counter-element 5 for taking up thewater migrating from the web W or the felts 51, 52. Especially in thiscase, the counter-roll 5 may comprise a suction roll or some otherporous or perforated or grooved-surface roll.

Thus, the web W can set in a direct contact with the counter-element 5,and the felts or wires, represented by numeral 52, can be omittedcompletely. In special applications, it is further possible to useembossed and/or engraved rolls or belts, should the fibrous W beprovided with some sort of pattern.

One of the main functions of the counter-element 5 is to operate both asa bearing surface and possibly also as a dewatering means. It is furtherconceivable to use the counter-element 5 as a heat source, such as in aso-called hot-pressing and impulse-drying process, which is known fromnumerous publications. The counter-element may comprise a thermal orpress roll (hard, ceramic-covered, or porous surface), a belt roll (shoeroll), a deflection-compensated roll, an elastic surface roll (rubber,polymer, etc.), a composite roll, or the like. The counter-roll may alsocomprise another belt loop, such as a metal or polymer belt, a wire, orthe like, which is respectively supported from inside the belt loop bymeans of a support element.

The counter-element 5 can also be heated. Thus, heating reduces theviscosity of water, possibly vaporizes water, and hence generates asteam pressure effect propelling water towards the felt. In addition,the heating of a web supplies the same with thermal energy which, as thepressure drops in a nip opening stage, results in powerful vaporization(so-called flashing).

The belt 2, the fibrous web W, the wires and/or felts 51, 52, as well asthe support element 4 can also be heated or cooled. Heating can becarried out by conventional means. The belt 2, for example, can beheated by induction.

In a particularly preferred case, if the felt is located “on theoutside” with respect to the curvature of a web, the result is awater-propelling centripetal force assisting in the migration of water.At high speeds and with small roll radii, the centripetal force can beso significant that the actual pressing action can be reduced or evenomitted. At the very least, the centripetal force works againstso-called rewetting, i.e. impedes a back flow of water from felt to web.FIG. 15 depicts an embodiment of the invention, wherein awater-accepting felt 51 is provided between a web W and a belt 2 andwherein the migration of water from the web W to the felt 51 is enhancedby means of a centripetal force. The effect has been further intensifiedby making the diameter of a roll 5 smaller than that of the roll 5 inthe embodiment of FIG. 14. In the process of reducing the size of a roll5, it is necessary to consider the bending strength requirements thatmust be satisfied by the belt 2 and the felts/wires.

In association with wire and felt loops are provided necessary washingand drying functions, as known from current solutions.

FIG. 16 illustrates a device according to this further aspect of theinvention for drying a fibrous web W, comprising, in addition to theweb, at least one belt or wire 2 capable of attaining a tension andforming a dense bearing surface, and at least one particularly porousand compressible felt/wire 51. On the opposite side of the web W lies awater-accepting wire/felt 52, which is porous but substantially lesscompressible than the first felt 51.

In the process of leading the fibrous web W and the felts 51 and 52 intoa pressing zone between a counter-element 5, in this case a roll, and abelt 2, the felt 51 first compresses, whereby a gas contained in itspores compresses and a pressure in the felt increases. As the pressureseeks to equalize or level out, the gas flows towards the web W andpropels water present in the web pores in front of it, forcing it tomigrate into the felt 52. In this respect, the phenomenon is similar towhat happens with an impulse press, but what is essential is that thepressure is provided by mechanical compression instead of vaporization.

What is essential is to dimension the pore volume and compressibility offelts relative to each other, appropriately with respect to both the webW and the applied forces/pressures for providing a desired pressuredifference and dewatering action.

Pressure control in a pressing zone can be further improved byregulating individually the pressure effect of a belt 2 as well aspossibly added belt loops lying inside or on top of each other, i.e., inpractice, by adjusting a tension thereof independently of each other.Likewise, the occurrence of delamination can be impeded by adapting theopening points of belt loops to take place successively, preferably atappropriate intervals. This is visualized in FIG. 16 by pressure zones91 and 92 established by belt loops 2 and 51.

In the embodiments of both FIG. 16 and 17, the compression can beenhanced by means of an extra loading roll 4, which can be adapted to bemovable for varying the length of a processing zone and/or the tensionof a belt 2. The roll 4 may also comprise a profiled roll. Moreover, inassociation with the belt and felt/wire loops are provided necessarywashing/drying actuators. Furthermore, in the arrangement of FIG. 16,the roll 5 may preferably comprise a suction roll, whereby the suctioneffect can be used for further enhancing the dewatering action as thepressure difference increases. Thus, the numbered felt in FIG. 16 can beomitted completely.

In this embodiment of the invention, as well, the roll/belt loop systemcan be preferably designed in such a way that there is a centripetalforce assisting in the migration of water in a radial direction of theroll 5, as illustrated in FIG. 17. Thus, the felt 51, which is morecompressible and from which air migrates towards a web W, is arrangedbetween the roll 5 and the web W on “the inside curve”. As air migratesfrom the felt 51 towards the web W and forces the water contained in theweb to migrate into a felt 52, the centripetal force further enhancesthis effect. FIG. 18 is a schematic close-up, illustrating a detail inthe exemplary embodiment of FIG. 17 from the region of a nip establishedby the extra loading roll 4. The figure visualizes the enhancing effectof a gas contained in the pore volumes of felts for drying the fibrousweb W within a pressing zone.

The following description deals with a fibrous web sizing process, withreference to the mechanical configuration shown in FIGS. 1-7.

When the question is about a stock or internal sizing process, thesizing agents are preferably admixed within stock by some conventionalmeans at the wet end upstream of the headbox of a paper machine, and,thus, it is not described further in this context. On the other hand,when the question is about surface or top sizing, the sizing agents canbe applied to the surface of a fibrous web W during the course of amanufacturing process in a prior known manner, not described further inthis context, either on-line or off-line, for example by using filmtransfer technology, by spraying or brushing. Application is preferablyeffected just before passing the fibrous web W into a processing zone ina metal belt calender.

Sizing can be preferably effected by using sizing agents, such as resinsobtained from softwood pitch, as well as synthetic AKD (alkylketenedimer) and ASA (alkenyl succinic anhydride) sizes. Wet strength sizesare used for enhancing wet tensile strength, and dry strength sizes areused for reinforcing the texture of dry paper. Dry strength sizescomprise, for example, starch and the above-mentioned synthetic sizes.

A fibrous web W to be treated is passed through a processing zone, beingsubjected to a desired pressure impulse and thermal effect as a functionof time. In the process of heating and compressing the fibrous web W ina contact zone, the sizing agents are finally bonded to fiber surfaces.In addition, the web develops new fiber bonds. Lignin, in particular,develops new bonds in addition to forming simultaneously a layerprotecting fibers from water. What is essential in a process of theinvention is that the application time for treating a fibrous web in aprocessing zone be sufficient, about 10-300 ms. The bonding of sizingagents to fiber surfaces is enhanced by raising the temperature of thefibrous web W to a sufficiently high level. Reference numeral 6 (FIG. 1)represents heating means for heating the metal belt 2, such as aninduction heater, an infrared radiator, or a gas burner. Heating can bebased also on resistive heating. A solution of the invention can beimplemented by using elevated temperatures, for example from about 200°C. to as high as about 400° C., depending on the thickness, moisture,and other properties of paper or board to be processed, sizing agentsapplied, as well as processing time.

The optional implementations for a processing device shown in FIGS. 1-7can be preferably used for treating a fibrous web W with sizing agents.The pressurized thermal treatment of a fibrous web for enhancing asizing process can be conceivably effected, according to the invention,also in the dryer section of a paper or board machine, in which case thebelt comprises a metal belt, and the counter-element establishing acontact area therewith comprises a drying cylinder. It is furtherconceivable that the treatment of a fibrous web for enhancing the effectof sizing agents be performed for example with a shoe press or aCondeBelt-type of arrangement, wherein two metal belts are adapted totravel in contact with each other over a certain distance.

Furthermore, particularly in the case of surface sizing, the eventualmoisture control of a fibrous web can be performed by conventionalmeans, for example by steaming the web surface/surfaces prior to leadingthe web into a processing zone. Moistening and/or temperature controlcan be used for an impact on the sizing process and, thus, the methodprovides a possibility for wide-range fluctuation of web moisture.

According to the invention, a feasibility is offered for providing aconcurrent sizing and calendering action. A metal belt calender of theinvention can be operated at considerably high speeds and also at anelevated temperature. The elevated temperature, together with a longapplication time and a wide pressure control range, can be used forproviding at the same time a good calendering result at both high andlow speeds, e.g. at speeds of 100 m/min to 4000 m/min. In addition, theinventive metal belt calender provides a supported web passage through aprocessing zone and allows for a controlled variation of web widthwithin the range defined by belt width. Web feeding is feasible over afull web width and at a high web speed.

FIGS. 19 and 20 illustrate schematically one pilot machine of theinvention in side and end views, respectively, the correspondingcomponents being indicated by the same reference numerals as in thepreceding figures. Reference numeral 20 represents a first verticalframe of the pilot device, on which are mounted, with a per se knownbearing assembly, first guiding rolls 3 for a belt 2. On the verticalframe 20 is further mounted, with a per se known bearing assembly, aguide roll 22 for a web W. Reference numeral 21 represents a secondvertical frame for a pilot device 1, on which are mounted second guidingrolls 3 for the belt 2, as well as a counter-roll 5 and a press roll 4.A processing zone is established between the belt 2 and the counter-roll5 and the web 5 is passed through said processing zone. The press roll 4remains inside the belt loop and is contactable by means of loadingelements 23 with the inner surface of the belt 2 for establishing,together with the counter-roll 5, a higher-pressure nip area within theprocessing zone.

FIG. 21 depicts one embodiment for an LWC paper production line, showingthe line sections downstream of a press section I. The press section isfollowed by a dryer section II, the tail end portion of which isindicated by reference symbol III. The dryer section is followed by aprecalendering process IV and then by a coating process V, which isdivided into a coating station Va and a drying portion Vb. The coatingstation is followed by a final calendering process VI and ultimately byfinishing processes VII, including e.g. winding operations. It isconceivable for a processing device of the invention to be located in anon-line production line for LWC paper, e.g. as indicated by referencesymbols a, b, c and/or d. In addition to or instead of these locations,it is conceivable that a processing device of the invention be used forreplacing, for example, the tail end portion III of a dryer sectionand/or the precalender IV and/or the final calender VI, the wet press I,the sizing device Va, or e.g. the coating device Vb.

Generally speaking, it can be concluded that the inventive processingdevice provides a very high efficiency for calendering and/or othertreatment in a single processing zone. The inventive device allows forvery extensive ranges for pressure, temperature and dwell times, whichare combinable in a variety of ways depending on a particularapplication. For example, a pressure domain can be within the range ofabout 0.01 MPa to about 70 MPa or even up to the reading of about 200MPa, temperature can be within the range of about −70° C. to about +400°C., and a dwell time in the processing zone e.g. within the range ofabout 0.01 ms to about 2 s, or even in the order of about 10 s.Moreover, various grades can be manufactured by using various machinespeeds. The inventive device may comprise an on-line or off-line device.

1. A processing device for processing at least one of a coated fibrousweb and an uncoated fibrous web, comprising at least one of a metal beltand a metal-based belt configured to extend around at least one guidingelement, at least one counter-element being disposed outside said beltto provide a contact area with the belt, such that the belt and thecounter-element establish therebetween a web processing zone for passingthe web to be processed therethrough, wherein a length of the processingzone is defined by at least one of the disposition of the guidingelement and the configuration of said at least one counter-element,wherein a processing time of the web in the processing zone is withinthe range of between about 10 ms and about 1000 ms, and wherein acontact pressure applied to the web in the processing zone is within therange of between about 0.01 MPa and about 200 MPa.
 2. A device as setforth in claim 1, wherein the processing device comprises at least oneof a calender, a coater, a film transfer device, a printing device, adrier, and a press.
 3. A device as set forth in claim 1, wherein thecounter-element comprises a roll selected from the group consisting of adeflection-compensated roll, an elastic surface roll, a polymer-coveredroll, a rubber-covered roll, an elastomer surface roll, a shoe roll, athermal roll, a metal roll, a filled roll, and a composite roll.
 4. Adevice as set forth in claim 3, wherein the roll comprises a thermalroll, and wherein an operating temperature of at least one of thethermal roll and the belt is within the range of between about 50° C.and about 400° C.
 5. A device as set forth in claim 3, wherein the rollcomprises a thermal roll, and wherein the operating temperature of atleast one of the thermal roll and the belt is within the range ofbetween about −70° C. and about +50° C.
 6. A device as set forth inclaim 4, wherein said operating temperature is higher than about 200° C.7. A device as set forth in claim 4, wherein the operating temperatureis within the range of between about 250° C. and about 300° C.
 8. Adevice as set forth in claim 1, wherein the belt has a thickness ofbetween about 0.1 mm and about 3 mm and a tensile stress within therange of between about 10 MPa and about 500 MPa.
 9. A device as setforth in claim 8, wherein a thickness of the belt is within the range ofbetween about 0.3 and about 1.5 mm.
 10. A device as set forth in claim1, wherein at least one press element is provided inside the belt forpressing the belt against the counter-element.
 11. A device as set forthin claim 10, wherein the press element comprises at least one rollselected from the group consisting of a deflection-compensated roll, anelastic surface roll, a polymer-covered roll, a rubber-covered roll, anelastomer surface roll, a shoe roll, a thermal roll, a metal roll, afilled roll, and a composite roll.
 12. A device as set forth in claim11, wherein the roll is shiftable for at least one of varying the lengthof the processing zone, varying a tension of the belt, and adjusting amagnitude and location of a pressure effect in the processing zone. 13.A device as set forth in claim 11, wherein the counter-element comprisesa second belt adapted to be driven around guiding elements, theprocessing zone being established between the two belts.
 14. A device asset forth in claim 1, wherein the press element comprises a second beltloop inside the belt.
 15. A device as set forth in claim 1, wherein thebelt comprises at least one of a steel-reinforced rubber belt and acovered belt.
 16. A device as set forth in claim 1, wherein the belt hasan embossed surface for providing a desired pattern on the web.
 17. Useof a device as set forth in claim 1 as at least one of a precalenderupstream of a coating process, a final calender downstream of a papermachine, a final calender downstream of a coating process, a breakerstack, a drying device, a coating device, a sizing device, a printingdevice, and a cooling device.
 18. A method for processing at least oneof a coated fibrous web and an uncoated fibrous web with a processingdevice, the processing device comprising at least one of a metal beltand a metal-based belt configured to extend around a guiding element, atleast one counter-element being disposed outside said belt to provide acontact area with the belt, such that the belt and the counter-elementestablish therebetween a web processing zone for passing the web to beprocessed therethrough, wherein the method comprises defining a lengthof the processing zone by at least one of the disposition of the guidingelement and by the configuration of the counter-element, processing theweb in the processing zone for between about 10 ms and about 1000 ms,and adjusting a contact pressure applied to the web in the processingzone to within the range of between about 0.01 MPa and about 200 MPa.19. A method as set forth in claim 18, wherein the method uses at leastone press element provided inside the belt for pressing the belt againstthe counter-element for enhancing a pressure pulse applied to the webpassing through the processing zone.
 20. A method as set forth in claim18, wherein the counter-element used in the method comprises a thermalroll having a temperature that is raised for processing the web to anelevated temperature within the range of between about 70° C. and about400° C.
 21. A method as set forth in claim 18, wherein the belt has atemperature that is raised for processing the web to an elevatedtemperature within the range of between about 150° C. and about 400° C.22. A method as set forth in claim 20, wherein the temperature of atleast one of the thermal roll and the belt is raised for processing theweb to an elevated temperature higher than about 250° C.
 23. A method asset forth in claim 18, wherein at least one of the belt and thecounter-element is cooled to a temperature of between about −70° C. andabout +50° C.
 24. A method as set forth in claim 18, wherein a pressurepulse applied to the web passing through the processing zone has apattern adjusted by at least one of a tension of the belt, theconfiguration of the press elements, a compression force applied to theweb by the press elements, and moving the press element.
 25. A device asset forth in claim 1, wherein the device comprises a cleaning deviceprovided downstream of the processing zone for cleaning the belt overthe paper web-facing surface thereof.
 26. A device as set forth in claim1, wherein the belt is heated and the device is provided with a coolingdevice for cooling the heated belt, along edges thereof, with at leastone of a water injection arrangement and an air injection arrangementfor eliminating high temperature differences in the belt along the edgethereof.
 27. A processing device for processing at least one of a coatedfibrous web and an uncoated fibrous web, comprising at least one of ametal belt and a metal-based belt configured to extend around a guidingelement, at least one roll being disposed outside said belt to provide acontact area with the belt, such that the belt and the roll establishtherebetween a web processing zone for passing the web to be processedtherethrough, wherein outside the belt is provided adeflection-compensated nip roll to establish a profiling nip with theroll, with the web being configured to travel through said profilingnip, wherein a length of the processing zone is defined by at least oneof the disposition of the guiding element and the dimensioning of theroll, wherein a processing time of the web in the processing zone iswithin the range of between about 10 ms and about 1000 ms, and wherein acontact pressure applied to the web in the processing zone is within therange of between about 0.01 MPa and about 200 MPa.
 28. A device as setforth in claim 27, wherein the processing device comprises at least onea calender, a coating device, a sizing device, a printing device, adrier, and a press.
 29. A device as set forth in claim 27, wherein theprofiling nip is established both upstream and downstream of theprocessing zone, the web being configured to travel through theprofiling nip both upstream and downstream of the processing zone.
 30. Adevice as set forth in claim 27, wherein the roll comprises adeflection-compensated roll.
 31. A device as set forth in claim 27,wherein the roll is selected from the group consisting of adeflection-compensated roll, an elastic surface roll, a polymer-coveredroll, a rubber-covered roll, an elastomer surface roll, a shoe roll, athermal roll, a metal roll, a filled roll, and a composite roll.
 32. Adevice as set forth in claim 31, wherein the roll comprises a thermalroll and an operating temperature of at least one of the thermal rolland the belt is within the range of between about 50° C and about 400°C.
 33. A device as set forth in claim 32, wherein said operatingtemperature is higher than about 200° C.
 34. A device as set forth inclaim 32, wherein the operating temperature is within the range ofbetween about 250° C. and about 300° C.
 35. A device as set forth inclaim 27, wherein the belt has a thickness of between about 0.1 mm andabout 3 mm and a tensile strength within the range of between about 10MPa and about 500 MPa.
 36. A device as set forth in claim 35, whereinthe belt thickness is within the range of between about 0.3 mm and about1.5 mm.
 37. A device as set forth in claim 27, wherein inside the beltis provided at least one press element for pressing the belt against theroll.
 38. A device as set forth in claim 37, wherein the press elementcomprises at least one roll selected from the group consisting of adeflection-compensated roll, an elastic surface roll, a polymer-coveredroll, a rubber-covered roll, an elastomer surface roll, a shoe roll, athermal roll, a metal roll, a filled roll, and a composite roll.
 39. Adevice as set forth in claim 27, wherein the roll comprises a secondbelt configured to be driven around guiding elements, such that theprocessing zone is established between the two belts.
 40. A device asset forth in claim 27, wherein the belt comprises at least one of asteel-reinforced rubber belt and a coated belt.
 41. A device as setforth in claim 27, wherein the belt has an embossed surface forproviding a pattern on the web.
 42. A device for drying a fibrous web,said device comprising at least one of a dense, air impermeable metalbelt and a dense, air impermeable metal-based belt, defining a surfaceand configured to extend around at least one guiding element, at leastone counter-element defining a surface and being disposed outside saidbelt to provide a contact area with the belt, the surfaces establishingtherebetween a fibrous web drying zone for passing the to-be-driedfibrous web through said drying zone, wherein one of the surfaces isheated and the other is cooled, at least one porous wire being furtherconfigured to travel between the surfaces such that the fibrous web isin contact with the heated surface and the wire is in contact with thecooled surface, any steam escaping from the fibrous web migratingthrough the wire to the cooled surface and condensing thereon, whereinthe belt extends about the counter-element in compliance with thesurface thereof, wherein a length of the drying zone is configured to beadjustable by at least one of the disposition of the guiding element andthe configuration of the counter-elements, wherein a drying time of theweb in the drying zone is within the range of between about 10 ms andabout 1000 ms, and wherein a contact pressure applied to the fibrous webis within the range of between about 0.01 MPa and about 70 MPa, suchthat the contact pressure applied to the fibrous web in the drying zoneis at least equal to a steam pressure generated by vaporization of watercontained in the fibrous web.
 43. A drying device as set forth in claim42, wherein the counter-element is heated and the belt is cooled.
 44. Adrying device as set forth in claim 42, wherein the counter-element iscooled and the belt is heated.
 45. A drying device as set forth in claim42, wherein the belt is heated.
 46. A drying device as set forth inclaim 45, wherein the counter-element is heated.
 47. A drying device asset forth in claim 42, wherein the counter-element comprises a rollconfigured to be heat conductive with respect to the surface thereof.48. A drying device as set forth in claim 47, wherein the roll comprisesa thermal roll, and wherein an operating temperature of at least one ofthe thermal roll and the belt is within the range of between about 20°C. and about 400° C.
 49. A drying device as set forth in claim 42,wherein the counter-element comprises a fixed support bar configured tobe heat conductive with respect to the surface thereof.
 50. A device asset forth in claim 42, wherein the belt has a thickness of between about0.1 mm and about 3 mm and has a tensile strength within the range ofbetween about 10 MPa and about 500 MPa.
 51. A device as set forth inclaim 42, wherein a thickness of the belt is within the range of betweenabout 0.3 mm and about 1.5 mm.
 52. A device as set forth in claim 42,wherein inside the belt is provided at least one press element forpressing the belt against the counter-element.
 53. A device as set forthin claim 52, wherein the press element comprises at least one rollselected from the group consisting of a deflection-compensated roll, anelastic surface roll, a polymer-covered roll, a rubber-covered roll, anelastomer surface roll, a shoe roll, a thermal roll, a metal roll, afilled roll, and a composite roll.
 54. A device as set forth in claim42, wherein the press element comprises a second belt loop providedinside the belt.
 55. A processing device for drying at least one of apaper web and a board web by pressing, said device comprising at leastone of a metal belt and a metal-based belt configured to extend aroundat least one guiding element, at least one counter-element beingdisposed outside said belt to establish a contact area with the belt,such that the belt and the counter-element establish therebetween a webprocessing zone for passing the web to be processed therethrough,wherein the device is provided between the belt and the counter-elementwith at least one of a porous felt and a wire capable of receiving waterto be removed from the fibrous web, wherein a length of the processingzone length is defined by at least one of the disposition of the guidingelement and the configuration of said at least one counter-element,wherein a processing time of the web in the processing zone is withinthe range of between about 10 ms and about 1000 ms, and wherein acontact pressure applied to the web in the processing zone is configuredto be within the range of between about 0.01 MPa and about 70 MPa.
 56. Adevice as set forth in claim 55, wherein the belt comprises at least oneof a metal belt, a metal wire, a composite metal belt, and a compositemetal wire, and wherein the belt is at least partially porous.
 57. Adevice as set forth in claim 56, wherein the counter-element comprisesat least one of a second belt loop, a thermal roll, a press roll, a shoeroll, a deflection-compensated roll, an elastic surface roll, acomposite roll or some other roll.
 58. A device as set forth in claim57, wherein the counter-element is at least one of configured as asuction roll, configured to have a porous surface, configured to have aperforated surface, and configured to have a grooved surface.
 59. Adevice as set forth in claim 55, wherein the belt is at least one ofheated and cooled.
 60. A method for drying at least one of a paper weband a board web by pressing in a processing device, comprising a beltconfigured to extend around at least one guiding element, at least onecounter-element being disposed outside said belt to establish a contactarea with the belt, such that the belt and the counter-element establishtherebetween a web processing zone for passing the web to be processedtherethrough, wherein the processing device is provided on both sides ofa web with a pore volume, wherein, at least on one side of the web, thepore volume is created in at least one of a compressible felt and wire,wherein the fibrous web to be dried is conveyed in contact with saidpore volumes through the processing zone, wherein said volumes aresubjected to a compression effect, whereby the at least on of the feltand wire compresses and at the same time the pressure of a gas presentin the pores thereof increases, resulting in a gas flow against the weband directing of water present in the web towards the pore volume on theother side of the web.
 61. A device as set forth in claim 60, whereinthe web is provided on both sides with at least one of a porous felt andwire, each having pore volumes with compressibilities substantiallydifferent from each other.
 62. A device as set forth in claim 60,wherein the web is provided on one side with at least one of a felt andwire and on the other side with at least one of a porous roll surfaceand a suction roll.
 63. A method for treating at least one of a coatedfibrous web and an uncoated fibrous web with a sizing agent, wherein atleast one sizing process for the fibrous web to be treated with thesizing agent comprises the use of a processing device as set forth inclaim 1 or 18, wherein a contact pressure applied to a web is adjustedby at least one of a tension of the belt and a compression force appliedto the belt by press elements optionally provided inside the belt loopto be within the range of between about 0.01 MPa and about 70 MPa.
 64. Amethod as set forth in claim 63, wherein the counter-element comprises aroll selected from the group consisting of a deflection-compensatedroll, an elastic surface roll, a polymer-covered roll, a rubber-coveredroll, an elastomer surface roll, a shoe roll, a thermal roll, a metalroll, a filled roll, and a composite roll.
 65. A method as set forth inclaim 63, wherein the counter-element comprises a second belt loop. 66.A method as set forth in claim 63, wherein the method comprises using atleast one press element inside the belt for pressing the belt againstthe counter-element for enhancing a pressure pulse applied to thefibrous web passing through the processing zone.
 67. A method as setforth in claim 63, wherein the method comprises at least one of aninternal sizing process and a stock sizing process for the fibrous web,wherein the sizing agents are admixed within a stock for producing theweb upstream of a headbox of a paper machine, and wherein the fibrousweb is then processed in the processing zone for enhancing the sizingprocess.
 68. A method as set forth in claim 67, wherein the fibrous webis processed for a processing time in the processing zone within therange of between about 10 ms and about 1000 ms.
 69. A method as setforth in claim 67, wherein the fibrous web is processed for a processingtime in the processing zone within the range of between about 50 ms andabout 200 ms.
 70. A method as set forth in claim 67, wherein a contactpressure applied to the fibrous web passing through the processing zoneis adjusted such that the contact pressure applied to the fibrous web inthe processing zone is at least equal to a steam pressure generated inprocessing the fibrous web.
 71. A method as set forth in claim 70,wherein the contact pressure is within the range of between about 0.01MPa and about 70 MPa.
 72. A method as set forth in claim 67, wherein aprocessing temperature of the fibrous web in the processing zone iswithin the range of between about 100° C. and about 400° C.
 73. A methodas set forth in claim 67, wherein a temperature of at least one of thecounter-element and the belt is raised for processing the fibrous web toa temperature range of between about 100° C. and about 400° C.
 74. Amethod as set forth in claim 73, wherein the temperature is within therange of between about 200° C. and about 300° C.
 75. A method as setforth in claim 63, wherein the method comprises using a metal beltcalender for surface sizing the fibrous web, and wherein the sizingagents are admixed within the fibrous web on a fibrous-web productionline.
 76. A method as set forth in claim 75, wherein a processing timeof the fibrous web in the processing zone of the metal belt calender iswithin the range of between about 10 ms and about 300 ms.
 77. A methodas set forth in claim 76, wherein the processing time of the fibrous webin the processing zone of the metal belt calender is within the range ofbetween about 50 ms and about 200 ms.
 78. A method as set forth in claim75, wherein a processing temperature of the fibrous web in theprocessing zone of the metal belt calender is within the range ofbetween about 100° C. and about 400° C.
 79. A method as set forth inclaim 78, wherein the processing temperature is within the range ofbetween about 200° C. and about 300° C.
 80. A method as set forth inclaim 75, wherein a contact pressure applied to the fibrous web passingthrough the processing zone is adjusted such that the contact pressureapplied to a fibrous web in the processing zone is at least equal to asteam pressure generated in processing the fibrous web.
 81. A method asset forth in claim 80, wherein the contact pressure is within the rangeof between about 0.01 MPa and about 70 MPa.
 82. A method as set forth inclaim 75, wherein a temperature of at least one of the counter-elementand the belt is raised in processing the fibrous web to a temperaturerange of between about 100° C. and about 400° C.